When her stepfather is arrested, aspiring artist Ceci moves back to her mother's hometown of Santa Aguas, an eccentric small town steeped in the legend of La Cegua, the specter of a wronged witch who appears on lonely roads at night, luring untrustworthy men to their deaths.
Ceci and her mother take up residence in the abandoned manor of the Sevilla family, rumored to have been cursed by La Cegua, where she begins to uncover a past connected to her mother. The more she learns of the Sevillas, the more Ceci finds herself forming a strange affinity with the feared Cegua, who she suspects is the one inspiring her paintings of a mysterious door in the forest.